This invention relates to a dispensing closure, i.e., a closure which permits the removal of the contents of the associated container through the closure without the removal of the closure. More particularly, this invention relates to a dispensing closure of the child-resistent or safety type in that, once properly applied to the associated container, it cannot be readily opened or removed from the container by children to permit the accidental spillage or ingestion of the contents of the container, while at the same time being capable of being opened by an adult without undue difficulty.
Prior U.S. Pat. Re. No. 29,793 (Pehr) and my prior U.S. Pat. Nos. 4,209,100 and 4,220,262 describe one-piece molded thermoplastic safety or child-resistent dispensing closures, and each such closure comprises a body member and an integrally attached locking flap which is foldable with respect to the body member and which snugly fits within a recess of the body member when it is in the closing position with respect to a dispensing opening in the body member. Each of such closures of my aforesaid U.S. Patents is child-resistent in that the body member of the closure comprises serrations to engage corresponding serrations of the associated container in the manner of a ratchet, after proper application thereto, to mechanically interfere with the removal of the closure from the container, and in that each is provided with structure which requires special manipulation to permit the removal of the locking flap from the recess of the body member to permit the removal of the contents of the container, or a portion thereof, through the body member. In the closure of U.S. Pat. No. 4,209,100 the special manipulation of the closure to permit the opening of the locking flap involves an initial squeezing of the opposite sides of the body member, and in the closure of U.S. Pat. No. 4,220,262 the special manipulation involves an initial step of applying a downward force on the central portion of the top of the closure, and in each of the closures the initial step is followed by a prying action against a portion of the locking flap which becomes exposed by the initial step. The closure of U.S. Pat. Re. No. 29793 also requires a prying action to disengage the locking flap from its closed position.
One of the problems with the closures described above is that the prying action referred to above involves the application of significant levels of prying force against surfaces which are exposed to a very limited extent by the initial step in the opening manipulation, and as a result the opening of these closures can on occasion lead to the breakage of fingernails. Another problem with each of these closures is that the child-resistent feature of the locking flap thereof cannot be readily circumvented or eliminated, which may be desirable in households which are not inhabited or regularly visited by young children, especially in households inhabited by one or more occupants with impaired hand dexterity due to arthritis or other disease or due to an injury.